Hydrostatic pump



Nov. 14, 1944. w'. sPREcHER ETAL HYDROS TAT I C PUMP Filed OCT.. l2, 1943 2 Sheets-Sheet 1 CLMLZ M r r/ l l, 7 7 f w. sPREcHER ErAL. 2,362,777

Nov. 14, 1944.

i I HYDROSTATIC PUMP Filed 001'.. 12, 1945 2 Sheets-Sheet 2 n 4 a l 2 n M m fr n I und...

Patentcd Nov. 14, 1944 p UNITED STATES vPATENT OFFICE n HYDROSTATIC PUMP Wayne Sprecher and Cecil Ware, Houston, Tex. Application October 12, 1943, Serial No. 505,971

t (ci. 10s-46) 4 Claims.

This invention relates to a hydrostatic pump specially designed for deep wells.

An object of the invention is to provide a pump of the character .described wherein the pumping piston may be operated by a liquid column thus dispensing with the use of the usual sucker rod.

A further object of the invention is to provide a pump wherein there is an outer and an inner column of liquid, the latter wlthinthe tubing and the former within the casing around the tubing with an upper cylinder and an upper piston reciprocable therein and effective to transmit power through the inner column'of liquid to a lower piston reciprocable in a lower cylinder and connected to a working plunger in the working cylinder of the pump.

It is to be noted that the lower piston above referred to is of greater cross sectional area than the upper piston and that therefore power will be transmitted through the inner liquid column from the upper piston to the lower, or driving, piston by means of differential pressures on pistons of different diameters.

Another object of the invention is to provide pumping equipment of the character described whereby the head of the outer column ofliquid will offset the weight of the inner column of the actuating uid when the pump is on the up, or intake, stroke.

With the above and other objects in view the invention has particular relation to certain novel features of construction, operation and arrangement of parts an example of which is given in this specification and illustrated in the accompanying drawings wherein:

Figures 1 and 2 show vertical sectionalviews of the upper and lower ends, respectively, of the pump showing the parts on down, or discharge, stroke.

Figures 3 and 4 show vertical sectional views, respectively, of the pump showing the parts on up, or intake, stroke.

Figure 5 shows a. cross sectional view taken on the line 5-5 of Figure 4.

Figure 6 shows a cross sectional view taken on the line 6--6 of Figure 4 and Fig. 'l shows a side view of the assembled pump partly in section.

Referring now more particularly to the drawings wherein like numerals of reference designate f the same parts in each of the gures the numeral I designates the well casing and the numeral 2 designates the .well tubing within the casing both of which extend to the ground surface.

Incorporated into the upper end of the tubend thereof,` there is the lower cylinder 6 wherein the lower driven piston 'I is mounted to reciprocate. This lower piston is of greater cross sectional area than the upper piston 4.

Screwed onto the lower end of the cylinder 6 there is a coupling 8 and within the cylinder 6 and resting on said coupling there is a coil spring 9 on which the piston 1 rests.

There is a surrounding tubular jacket ID whose lower end is screwed onto the upper end of the coupling 8 and whose upper end may be welded to a bushing II which surrounds, and may be welded to, the tubing 2.

Screwed into vthe lower end of the coupling 8 there is the working cylinder I2 in which the working, or pumping, plunger I3 reeiprocates. This plunger is connected with the piston 'I above by means of apiston rod I4 which -works through a stufling box I5 in the coupling 8.

The jacket I0 may be corrugated or other-l wise reinforced to withstand abnormal pressure, if it is found to be desirable. This jacket forms a fluid tight chamber I6 and a series of ducts Il lead from this chamber through the coupling 8 into the upper end of the working cylinder I2; andanother series of ducts I8 lead from the lower end of the cylinder G into the annular space I9 between the pump and the outer casing i.

Screwed onto the lower end of the working cylinder I2 there is the valve body I9 having the annular inlet valve seat 20 clamped therein by the ring nut y2l and said seat "iscontrolled by the upwardly opening ball valve 22. The valve body I9 also has the ducts 23 leading upwardly from the central chamber 24 thereof and controlled by the upwardly opening ball valves 25. The body I9 has side outlets as 26 through which the pumped liquid enters the annular i space I9.

'I'he tubing 2 continues on down beneath the pump and is sealed with the casing I by means of a packer 21 of any conventional type and beneath the packer tubing is perforated forming a screen 28.

The chamber I6 may contain either air or inert gas and is of such volume that there will only be a slight change of pressure therein as the plunger I3 moves from one end of its stroke to the other. A small quantity of high grade lubricating oil as 28 is contained in the chamber IB to assist in maintaining a proper seal between the upper portion of the plunger Il and the wall of the cylinder I2 as well as between the rod I4 and the stulling box I I and to lubricate these parts effectively.

The purpose of the chamber Il and the air or gas therein is to provide an elastic medium which permits a free movement of the plunger I3 and at the same time sealing oi! all head pressure from the space I9 against the upper end of the plunger I3.

The ducts I8 are provided for the entrance and exit of the liquid in the outer column in the space I9 into and from the lower cylinder 6 thus causing the liquid head to bear against the lower face o! the piston 1. Any degree of equilibrium may be maintained between Vthe columns of liquid depending upon the head pressure ci' the outer column; and since the operating liquid in the inner column may be of much lower specific gravity than that in the other column, or space I9, a further differential is achieved to aid in osetting the difference in areas between the upper and lower faces of the piston l. Thus it is clear that by adjusting the head on the liquid column in the space I9, the opposing columns may be placed in exact equilibrium if desirable.

The spring 9 is installed in the assembly to normally maintain the piston l and plunger I3 in their upper position-during manufacturing and installation operations and also to aid in overcoming the columnar inertia. It also aids in some respect to lift the piston and plunger assembly.

With the pump installed and the, parts inthe position shown in Figures 3 and 4 on downward movement of the piston l the liquid column in the tubing 2 will transmit the power by diierential pressure to the piston and plunger assembly 'I, I4, i3, forcing it downwardly and compressing the spring 9 thus forcing the liquidv in the cylinder S out through the channels I 8 into the space I 9V and drawing lubricant and compressed iluid from the chamber I to the upper part of the working cylindvr I2. The well liquid to be pumped having been drawn into the lower part of the cylinder I2 through the intake valve 22 on the previous intake stroke will be forced out through'the channels 23 past the valves 25 and into the space Il where it becomes a part of the outer column, as indicated in Figure 2.

Upon upstroke, the head pressure of the outer column having been increased to an amount equal to the displacement involved, the well liquid havacca??? into the chamber Il and liquid from the column in the space I8 passes through the ducts I8 and applies pressure to the underside of the piston ing been suitably drawn off, at the ground surface, now acts to seek equilibrium with the actuating iluid in the tubing-2 and becomes eiective immediately upon the upstroke of the piston I. 'I'he air or gas together with the lubricant in the upper part of the cylinder I2 are returned 'I which piston, aided in part by the spring 9, moves upwardly thus moving the plunger I3 upwardly and drawing in another charge of liquid past the intake valve 22. The operating liquid column in the tubing I is returned to its original level and thus the cycle is completed.

As illustrated upon upward movement of the piston l the weight of the column of pumped liquid in the casing I will act against the lower end of the piston 'l to move said piston, and the plunger' I3, upwardly and another charge of well liquid will ilow into the pumping cylinder I2. It is obvious that, if desired, equipment may be provided at the ground surface for supplementing the weight of the column of pumpediluid by the application of pressure thereto, provision being made also for taking of! the pumping gain upon downstroke, or power stroke, of the plunger I3 and in this case the power applied will be fully controlled in both directions.

What we claim is:

1. In pumping equipment a pumping cylinder, a pumping plunger reciprocable therein, a well tubing, a cylinder associated with the tubing and having a piston therein, a piston rod connecting the piston and plunger, a seal .around said rod, a chamber for containing a compressible iuid with a duct leading therefrom into the upper end of the pumping cylinder.

2. In pumping equipment a pumping cylinder, a pumping plunger reciprocable therein, a well tubing, a cylinder associated with the tubing and having a lower end port, a piston in said cylinder above said port, a piston rod connecting the piston and plunger, a seal around said rod between said cylinders, a chamber for containing a compressible uid and provided with a duct leading therefrom into the upper end of the pumping cylinder.

3. In pumping equipment a pumping cylinder, a pumping plunger reciprocable therein, a well tubing, a cylinder associated with the tubing and having a piston therein, a piston rod connecting the piston and plunger, a seal around said rod, a chamber for containing a compressible iluid with a duct leading therefrom into the upper end of the pumping cylinder, a compressible uid and a liquid lubricant in said chamberv movable back and forth through the duct as the plunger reciprocates.

4. In pumping equipment a pumping cylinder, a pumping plunger reciprocable therein, a well tubing, a cylinder associated with the tubing and having a piston therein, a yieldable member supporting the piston, a piston rod connecting the piston and plunger, a seal around said rod, a chamber for containing a compresslble iluid with a duct leading therefrom into the upper end of the pumping cylinder.

' WAYNE SPRECHER.

CECIL WARE. 

